1. Field of the Invention
The present invention relates to a compressed air energy-storing electricity generating system and an electricity generating method using the same, and more particularly to a compressed air energy-storing electricity generating system and an electricity generating method using the same, in which air of a high pressure is injected into a tank laid under the ground using midnight electricity and surplus produced electricity, and the air of the high pressure in the tank is uniformly discharged so as to drive a generator during a time period when the consumption of electric power is high, thus efficiently managing energy.
2. Description of the Related Art
Midnight electricity means electricity used late at night from 10 pm of one day to 8 am of the next day or from 11 pm of one day to 9 am of the next day when the consumption of electricity is low, and has an inexpensive electric charge due to the supply of surplus electric power. Thus, various methods for using midnight electricity have been proposed. Representative apparatuses for using midnight electricity include a regenerative boiler using midnight electricity and a regenerative water heater using midnight electricity. These apparatuses store midnight electricity by night and use the stored electricity by day so as to disperse the consumption of electricity power concentrated on the daytime.
Further, according to another method for using midnight electricity, compressed air is stored in an underground cave using midnight electricity and the stored compressed air is supplied to a turbine by day so as to drive a generator, thus reducing the consumption of electric power by day.
As shown in FIG. 4, in a conventional compressed air energy storage (CAES) system using midnight electricity, air compressed by a compressor 20, driven using midnight electricity, is injected into a storage tank 30, and the stored compressed air is discharged to the outside during a time period when the consumption of electric power is high. The discharged compressed air is mixed with a fuel in a burner 50 such that the mixture of the air and the fuel is burned, and a turbine 40 is driven by the pressure of the burnt gas. Thereby, a generator is driven.
Such a system compresses air using midnight electricity, and uses energy converted from the compressed air if necessary. However, as the compressed air is continuously discharged to the outside, the pressure in the storage tank 30 is gradually lowered and the pressure of the discharged compressed air is gradually lowered, and thus a turbine driving efficiency is depreciated. Accordingly, an apparatus, which can continuously discharge compressed air stored at a uniform pressure, has been strongly required.